Spring contact and test socket with same

ABSTRACT

The present invention relates to a test socket having a thin structure that can reduce durability degradation of a contact itself, have excellent electrical characteristics in processing high-speed signals, and can extend a service life thereof, and relates to spring contacts suitable thereto. The test socket according to the present invention includes: a plurality of spring contacts ( 100 ) each of which includes an upper contact pin ( 110 ) and a lower contact pin ( 120 ) that are assembled cross each other, and a spring ( 130 ) supporting the upper and lower contact pins ( 110  and  120 ); a main plate ( 1110 ) having a plurality of accommodating holes ( 1111 ) in which the respective spring contacts ( 100 ) are accommodated, with first openings ( 1113 ); and a film plate ( 1120 ) provided on a lower portion of the main plate ( 1110 ), and having second openings ( 1121 ).

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No.10-2019-0122622, filed Oct. 2, 2019, the entire contents of which isincorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates generally to a spring contact and a testsocket with the same. More particularly, the present invention relatesto spring contacts that electrically connects each of a plurality ofleads of an integrated circuit (IC) to an associated one of a pluralityof pads of a printed circuit board (PCB) for the test of the performanceof the IC or electrically connects each of the leads of an IC of a CPUto a PCB of an electronic appliance such as a personal computer (PC) ora mobile phone, and relates to a test socket with the same.

Description of the Related Art

In general, spring contacts serve to electrically connect a PCB withleads of an IC, and are essential components of a socket for testingICs.

FIGS. 1A to 3B illustrate spring contacts in the related art, and FIGS.4 and 5 illustrate a socket with spring contacts.

FIGS. 1A and 1B are respectively a perspective view and an explodedperspective view illustrating spring contacts in the related art. Thespring contact includes an upper contact pin 10, a lower contact pin 20assembled to the upper contact pin 10 in such a manner that the upperand lower contact pins cross each other in longitudinal directionsthereof, and a spring 30 fitted over the upper and lower contact pins 10and 20 at a position therebetween to elastically support the upper andlower contact pins 10 and 20.

FIGS. 2A and 2B are respectively a plan view illustrating the uppercontact pin in the related art and a sectional view taken along lineA-A. The upper contact pin 10 includes a contact portion 11 protrudingfrom an upper end of the upper contact pin, a pair of fixing protrusions12 protruding from left and right sides of the upper contact pin, a bodyportion including a flow groove 13 a recessed in a longitudinaldirection thereof, a pair of elastic portions 14 extending symmetricallyfrom the body portion 13, and a locking protrusion 15 provided at an endof each of the elastic portions 14. Meanwhile, the lower contact pin hasthe same shape as the upper contact pin.

FIGS. 3A and 3B are respectively views illustrating an operation exampleof the spring contact in the related art, in which the left and rightviews of FIG. 3A illustrate respectively before and after compression ofthe spring, and the left and right views of FIG. 3B illustrate in planview the position between the upper and lower contact pins before andafter the compression of the spring.

Referring to FIGS. 3A and 3B, the upper contact pin 10 and the lowercontact pin 20 are assembled together with the spring 30 fittedthereover in such a manner that the elastic portions 14 and 24 areperpendicular to each other in the longitudinal directions of thecontact pins. In detail, the respective locking protrusions 15 of theupper contact pin 10 are inserted into a flow groove 23 a of the lowercontact pin 20 and locking protrusions 25 of the lower contact pin 20are inserted into the flow groove 13 a of the upper contact pin 10.Therefore, when an external force acts in a longitudinal direction ofthe spring contact, the locking protrusions 15 and 25 are moved alongthe flow grooves 13 a and 23 a while the upper contact pin 10 and thelower contact pin 20 are compressed by a certain length S.

Referring to FIG. 3A, the maximum displacement (Smax) between the uppercontact pin 10 and the lower contact pin 20 is determined by theposition (left view) where the locking protrusions 15 and 25 of theupper and lower contact pins 10 and 20 are supported at the ends of theopposing flow grooves 13 a and 23 a before the spring is compressed, andthe position (right view) where end portions 13 b and 23 b of the bodies13 and 23 of the upper and lower contact pins 10 and 20 come intocontact with each other in a compressed state of the spring.

FIG. 4 is a plan view illustrating the socket in the related art, andFIG. 5 is a sectional view taken along line B-B of FIG. 4.

Referring to FIGS. 4 and 5, the socket in the related art includes anupper plate 40 and a lower plate 50 assembled to the upper plate 40 byfitting, with spring contacts 1 fixed between the upper plate 40 and thelower plate 50.

The upper plate 40 and the lower plate 50 include respectively receivingholes 41 and 51 to which the spring contact 1 is fixed. The springcontact 1 is located in the receiving holes 41 and 51 between the upperand lower plates 40 and 50 such that upper and lower ends thereofprotrude outside the receiving holes 41 and 51, and serves toelectrically connect a lead of an IC and a pad of a PCB to each other.

The socket in the related art is manufactured in such a manner that theupper and lower plates are made of synthetic resin. In particular, atthe upper plate 40, a flange portion 42 in which the first receivinghole 41 is formed is provided by protruding from the upper plate 40 by apredetermined height such that the spring contact 1 of a predeterminedheight is received therein.

Therefore, in a manufacturing a thin-type plate having the above flangeportion in which the first receiving hole by injection molding withsynthetic resin, a high processing cost is required. Also, there is alimitation in manufacturing a plate having a thickness of equal to orless than 1.0 mm, and, due thereto, it is difficult to manufacture atest socket for high speed use for processing a high-speed signal ofequal to or greater than 40 GHz.

On the other hand, as another related art technology, a rubber-typesocket is used. The rubber socket may include a stretchable insulatingbody having an insulating silicone powder solidified therein, and aconductive silicone portion formed in the insulating body by verticallypassing therethrough at a position corresponding to a lead of an IC.

The rubber-type socket may be manufactured in such a manner that when asilicone mixture containing insulating silicone and conductive powder ina predetermined ratio is placed into a mold and a strong magnetic fieldis formed at a position where the conductive silicone portion is to beformed, the conductive powder of the silicon mixture is collected at theposition where the magnetic field is formed and finally a moltensilicone mixture is solidified to form an array of conductive siliconeportions in the insulating body.

The rubber-type socket is disadvantageous in that the speed of elasticresponse may be slower than that of a pin-type contact (spring contact)and the elasticity may be lost in the course of a repeated test process,which may result in a short service life and increased costs due tofrequent replacement. In addition, due to the characteristics that theelasticity persistence decreases over time, the elastic repulsive forcemay become zero or remarkably low during continuous compression test fora long period of time (more than one week), and thus a short circuit mayoccur, which may make it difficult to use the rubber-type socket forlong term testing.

Moreover, the rubber-type socket is problematic in that the elasticcharacteristics may be affected greatly by the temperature, and theuniformity of the resistance characteristics of the individualconductive silicone portions may be inferior.

The foregoing is intended merely to aid in the understanding of thebackground of the present invention, and is not intended to mean thatthe present invention falls within the purview of the related art thatis already known to those skilled in the art.

DOCUMENTS OF RELATED ART

(Patent document 1) Korean Patent Application Publication No.10-2011-0051668 (published on May 18, 2011)

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the related art, and an objective of thepresent invention is to provide a socket having a thin structure thatcan reduce durability degradation of a contact itself, have excellentelectrical characteristics in processing high-speed signals, and canextend a service life thereof, and to provide a spring contact suitablethereto.

In order to achieve the above objective, according to one aspect of thepresent invention, there is provided a test socket with spring contacts,the test socket including: a plurality of spring contacts each of whichincludes an upper contact pin, and a lower contact pin assembled to theupper contact pin such that the upper and lower contact pins cross eachother to mutually linearly operate, and a spring elastically supportingthe upper contact pin and the lower contact pin; a main plate having aplurality of accommodating holes in which the respective spring contactsare accommodated, with first openings each having a diameter d2 smallerthan a diameter d1 of each of the accommodating holes formed to supporteach of the respective upper contact pins by a stepped portionprotruding horizontally from an upper opening end of each of theaccommodating holes; and a film plate provided on a lower portion of themain plate, and having second openings that each at a positioncorresponding to each of the accommodating holes to have a diameter d3smaller than the diameter d1 of the accommodating hole to support eachof the respective lower contact pins.

According to another aspect of the present invention, there is provideda test socket with spring contacts, the test socket including: aplurality of spring contacts each of which includes an upper contactpin, and a lower contact pin assembled to the upper contact pin suchthat the upper and lower contact pins cross each other to mutuallylinearly operate, and a spring elastically supporting the upper contactpin and the lower contact pin; a main plate having a plurality ofaccommodating holes in which the respective spring contacts areaccommodated, with first openings each having a diameter d2 smaller thana diameter d1 of each of the accommodating holes formed to support eachof the respective upper contact pins by a stepped portion protrudinghorizontally from an upper opening end of each of the accommodatingholes; and a silicone caulking part inserted into a lower opening end ofeach of the accommodating holes to fix each of the respective lowercontact pins to the main plate.

According to still another aspect of the present invention, there isprovided a test socket with built-in contacts, the test socketincluding: a plurality of spring contacts each of which includes anupper contact pin, and a lower contact pin assembled to the uppercontact pin such that the upper and lower contact pins cross each otherto mutually linearly operate, and a spring elastically supporting theupper contact pin and the lower contact pin; a lower film plate having aplurality of first through-holes through which the respective springcontacts are positioned; a mounting part provided on an upper side ofthe lower film plate; an insulating body provided on an upper side ofthe mounting part and having second through-holes formed correspondingto the first through-holes to accommodate the spring contacts; an upperfilm plate provided on an upper surface of the insulating body andhaving third through-holes formed corresponding to the secondthrough-holes; and a first silicone caulking part inserted into an upperportion of each of the second through-holes of the insulating body tofix each of the respective upper contact pins to the insulating body.

According to still another aspect of the present invention, there isprovided a test socket with built-in spring contacts, the test socketincluding: a plurality of spring contact each of which is integrallyformed in such a manner that a strip pattern formed by punching out ametal plate is rolled into a cylindrical shape; a lower film platehaving a plurality of first through-holes through which the respectivespring contacts are positioned; a mounting part provided on an upperside of the lower film plate; an insulating body provided on an upperside of the mounting part and having second through-holes that areformed corresponding to the first through-holes to accommodate thespring contacts; an upper film plate provided on an upper surface of theinsulating body and having third through-holes formed corresponding tothe second through-holes; and a first silicone caulking part insertedinto an upper portion of each of the second through-holes of theinsulating body to fix an upper end of each of the spring contacts tothe insulating body.

According to still another aspect of the present invention, there isprovided a spring contact, including: a first contact pin; a secondcontact pin assembled to the first contact pin such that the first andsecond contact pins cross each other; and a coil spring elasticallysupporting the first contact pin and the second contact pin, whereineach of the first contact pin and the second contact pin includes: abody portion including a groove that is recessed in each of oppositesurfaces thereof in a longitudinal direction thereof; a pair of shoulderprotrusions protruding from each of left and right side ends of the bodyportion to support the coil spring; a first end contact portionextending from an upper end of the body portion; a pair of elasticportions extending in the longitudinal direction of the body portion tobe bilaterally symmetrical to each other, and each of which includes aguide surface protruding inward from an end portion of each of theelastic portions such that the respective guide surfaces face eachother; and a second end contact portion extending from an end of each ofthe elastic portions, wherein at least one of the first end contactportion and the second end contact portion includes a head portionformed at the upper end of the body portion and made of a plate-shapedstrip, the strip having same left and right lengths with respect to of acenter of the body portion, with an upper end along which the first endcontact portion is formed, and the strip includes a first strip sectionlocated on the same plane as the body portion and provided to have thesame left and right distances from the center of the body portion, and asecond strip section rolled at each of opposite ends of the first stripsection to have a semi-circular arc shape, such that the first stripsection is located in a radial direction of a cylindrical shape formedby the entire second strip section.

The test socket according to the present invention has a structure withspring contacts and can be manufactured in a thin structure, and thushas an effect of being excellent in processing high-speed signals and ofextending a service life thereof.

In addition, the spring contact according to the present invention hasan effect of reducing the contact resistance in consideration of theshape of a lead of an IC, while having a structure suitable for the testsocket of the thin structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objectives, features, and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings, in which:

FIGS. 1A and 1B are respectively a perspective view and an explodedperspective view illustrating a spring contact in the related art;

FIGS. 2A and 2B are respectively a plan view illustrating an uppercontact pin in the related art and a sectional view taken along lineA-A;

FIGS. 3A and 3B are views illustrating an operation example of thespring contact in the related art;

FIG. 4 is a plan view illustrating a socket in the related art;

FIG. 5 is a sectional view taken along line B-B in FIG. 4;

FIG. 6 is an exploded perspective view illustrating a spring contactaccording to an embodiment of the present invention;

FIGS. 7A and 7B are respectively a plan view and a side viewillustrating an upper contact pin according to a first embodiment of thepresent invention;

FIGS. 8A, 8B, and 8C are views illustrating an extended state of thespring contact according to the first embodiment of the presentinvention;

FIGS. 9A, 9B, and 9C are views illustrating a compressed state of thespring contact according to the first embodiment of the presentinvention;

FIGS. 10A, 10B, and 10C are views illustrating a spring contactaccording to a modification of the first embodiment of the presentinvention;

FIGS. 11A to 14B are views illustrating a spring contact according to asecond embodiment of the present invention;

FIGS. 15A and 15B are views illustrating a modification to the secondembodiment of the present invention;

FIGS. 16 to 18 are views illustrating a spring contact according to athird embodiment of the present invention;

FIGS. 19A and 19B and FIGS. 20A and 20B are views illustratingmodifications of the third embodiment of the present invention;

FIG. 21 is a plan view illustrating a test socket according to a firstembodiment of the present invention;

FIG. 22 is a cross-sectional view taken along line E-E in FIG. 21;

FIG. 23 is a sectional view illustrating a test socket according to asecond embodiment of the present invention;

FIG. 24 is a sectional view illustrating a test socket according to athird embodiment of the present invention;

FIGS. 25 and 26 are sectional views illustrating a test socket accordingto a fourth embodiment of the present invention;

FIG. 27 is a sectional view illustrating a test socket according to afifth embodiment of the present invention;

FIG. 28 is a sectional view illustrating a test socket according to asixth embodiment of the present invention; and

FIG. 29 is a sectional view illustrating a test socket according to aseventh embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

All terms or words used in the specification and claims have the samemeaning as commonly understood by one of ordinary skill in the art towhich inventive concepts belong. It will be further understood thatterms, such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized or overly formal sense unless expressly so defined herein.

Accordingly, one or more embodiments and configurations illustrated indrawings are only exemplary embodiments, and do not represent alltechnical aspects of the present invention. Thus, it should beunderstood that there may be various equivalents and changes capable ofreplacing the one or more exemplary embodiments.

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.

First Embodiment

FIG. 6 is an exploded perspective view illustrating a spring contactaccording to a first embodiment of the present invention. A springcontact 100 of the present embodiment includes an upper contact pin 110,a lower contact pin 120 assembled to the upper contact pin 110 such thatthe upper and lower contact pins 110 and 120 cross each other, and aspring 130 elastically supporting the upper and lower contact pins 110and 120.

In particular, the upper contact pin 110 and the lower contact pin 120according to the present invention are provided by the use of contactpins having the same size and shape. Two contact pins 110 and 120assembled to cross each other in longitudinal directions thereof aredivided into upper and lower contact pins depending on the assemblyposition.

Therefore, in the following description, the upper contact pin 110 willbe described mainly.

The spring 130 is provided by the use of a coiled compression springthat resists the compressive force. The spring 130 is provided betweenthe upper contact pin 110 and the lower contact pin 120 to provide arestoring force for returning the upper contact pin 110 and the lowercontact pin 120 to original positions thereof when the upper contact pin110 and the lower contact pin 120 are compressed in the longitudinaldirections thereof.

FIGS. 7A and 7B are respectively a plan view and a side viewillustrating the upper contact pin according to the first embodiment ofthe present invention.

Referring to FIGS. 7A and 7B, the upper contact pin 110 according to thepresent embodiment is provided by the use of a plate-shaped contact pinhaving a predetermined length L1, a predetermined width w1, and apredetermined thickness t1. In detail, the upper contact pin 110includes a body portion 112 including a groove 111 that is recessed ineach of opposite surfaces thereof in a longitudinal direction thereof, ashoulder protrusion 113 formed to protrude vertically from each of leftand right side ends of the body portion 112, a pair of first end contactportions 114 integrally extending from opposite sides of an upper end ofthe body portion 112 to be symmetrical each other with respect to therespective grooves 111, a pair of elastic portions 115 extending in thelongitudinal direction of the body portion 112 to be bilaterallysymmetrical to each other, a second end contact portion 116 formed at anend of each of the elastic portions 115, and a guide surface 117protruding inward from an end portion of each of the elastic portions115 such that the respective guide surfaces 117 face each other.

The body portion 112 is configured such that the groove 111 recessedwith a predetermined width and a predetermined depth along the centralaxis in the longitudinal direction thereof is provided in each of boththe opposite surfaces thereof. Each of the respective grooves 111 isconfigured such that an upper end thereof is open at the upper end ofthe body portion 112 while a lower end thereof has a hook locking step111 a having a step height. The entire body portion 112 has thepredetermined thickness t1, while a groove section of the body portion112 where the grooves 111 are formed has a thinner thickness t2 (t2<t1).

The body portion 112 includes a pair of shoulder protrusions 113protruding to extend from the left and right side ends thereof. Theseshoulder protrusions 113 support the spring 130. Meanwhile, the maximumwidth of the upper contact pin 110 is determined by the width w1 betweenthe two shoulder protrusions 113.

The first end contact portions 114 integrally extend from the upper endof the body portion 112 to be bilaterally symmetrical to each other.Preferably, each of the first end contact portions 114 includes an edgeline formed by two different contact surfaces that are in contact eachother. In the present embodiment, each of the first end contact portions114 is illustrated that first contact surfaces 114 a and 114 b comprisedof two curved surfaces are in contact with each other to form an upperedge line. Herein, the contact surfaces may be curved surfaces having apredetermined curvature or inclined surfaces having a predeterminedangle of inclination. The first end contact portions 114 are portionsthat come into line contact with a lead of an IC.

The elastic portions 115 are arranged spaced apart from each other by apredetermined width w2 in the longitudinal direction of the body portion112 to be bilaterally symmetrical each other. Each of the elasticportions 115 has the end portion provided with the guide surface 117protruding inward such that the respective guide surfaces 117 face eachother. An inflection end 117 a extending from the end portion of each ofthe elastic portions 115 to the guide surface 117 acts as a hook tolimit upward and downward movement between the two contact pins.

Therefore, a width w3 between the guide surfaces 115 of the respectiveelastic portions 115 is shorter than the width w2 between the twoelastic portions 115 (w3<w2). Preferably, the width w3 between the twoguide surfaces 115 is equal to or greater than a thickness t2 of thegroove section of the body portion 112 where the grooves 111 are formed(t2≤w3). In addition, the width w2 between the two elastic portions 115is equal to or greater than the thickness t1 of the body portion 112(t≤w2).

When the upper contact pin and the lower contact pin are assembled, theguide surfaces 117 of the upper contact pin are inserted into grooves ofthe lower contact pin while guide surfaces of the lower contact pin areinserted into the grooves 111 of the upper contact pin, and each guidesurface comes into contact with a bottom surface of each groove to serveto allow the upper and lower contact pins to be electrically connectedto each other.

A lower end edge of the body portion 112 located adjacent between thetwo elastic portions 115 includes a chamfered inclined surface 112 ahaving an inclination. The chamfered inclined surface 112 a serves tofacilitate assembly between the elastic portions 115 when the twocontact pins are assembled.

The second end contact portion 116 extends vertically from the end ofeach of the elastic portions 115. Preferably, each of the respectivesecond end contact portions 116 includes an edge line formed by twodifferent contact surfaces that are in contact with each other. In thepresent embodiment, each of the second end contact portions 116 isillustrated that second contact surfaces 116 a and 116 b comprised oftwo curved surfaces are in contact with each other to form an upper edgeline. Herein, the contact surfaces may be curved surfaces having apredetermined curvature or inclined surfaces having a predeterminedangle of inclination. The second end contact portions 114 are portionsthat come into line contact with a lead of an IC.

Preferably, a length L3 of the elastic portions 115 including the secondend contact portions 116 is longer than a length L2 from the first endcontact portions 114 to the lower end of the body portion 112 (L2<L3).

FIGS. 8A, 8B, and 8C are views illustrating an extended state of thespring contact according to the first embodiment of the presentinvention, in which FIG. 8A is a perspective view, and FIGS. 8B and 8Care sectional views in directions perpendicular to each other.

Referring to FIGS. 8A, 8B, and 8C, the upper contact pin 110 and thelower contact pin 120 are assembled in the longitudinal directionsthereof such that the respective elastic portions 115 and 125 cross eachother, and the spring 130 is supported by the shoulder protrusions 113and 123 of the upper and lower contact pins 110 and 120 to maintain theupper and lower contact pins 110 and 120 in an extended state.

In such an extended state of the spring contact 100, the first endcontact portions 114 of the upper contact pin 110 are exposed outside anupper end of the spring 130, while second end contact portions 126 ofthe lower contact pin 210 are located inside the spring 130. On thecontrary, first end contact portions 124 of the lower contact pin 120are exposed outside a lower end of the spring 130, while the second endcontact portions 116 of the upper contact pin 110 are located inside thespring 130.

FIGS. 9A, 9B, and 9C are views illustrating a compressed state of thespring contact according to the first embodiment of the presentinvention, in which FIG. 9A is a perspective view, and FIGS. 9B and 9Care sectional views in directions perpendicular to each other. In FIGS.9B and 9C, an upper view located above the spring contact illustrates alead ball of an IC in plan view, which illustrates a contact portionbetween end contact portions and the lead ball.

Referring to FIGS. 9A, 9B, and 9C, a total length L1 of the springcontact 100 in a compressed state is the same as the length L1 of asingle contact pin (see FIG. 7). Herein, the first end contact portions114 of the upper contact pin 110 and the second end contact portions 126of the lower contact pin 120, which define an upper end portion of thespring contact 100, come into contact with a lead ball 1 of an ICsimultaneously at four positions 114A and 126A in directionsperpendicular to each other.

Similarly, also in the case of a lower end portion of the spring contact100, the second end contact portions 116 of the upper contact pin 110and the first end contact portions 124 of the lower contact pin 120 comeinto contact with a lead (not illustrated) of a PCB simultaneously.

As described above, the spring contact 100 according to the presentinvention is characterized in that electrical contact of the end contactportions with the lead ball 1 is established at four plural positions ina compressed state of the spring contact. Advantageously, a reduceddesign of the length L1 of the spring contact is also possible, therebyminimizing electrical resistance.

FIGS. 10A, 10B, and 10C are views illustrating a spring contactaccording to a modification of the first embodiment of the presentinvention, in which FIG. 10A is a sectional view, FIG. 10B is a planview illustrating an upper contact pin, and FIG. 10C is sectional viewtaken along line D-D. In FIG. 10A, an upper view located above thespring contact illustrates a lead 2 of a land-type IC in plan view,which illustrates a contact portion between end contact portions and thelead.

Referring to FIGS. 10A, 10B, and 10C, a spring contact 200 of thepresent embodiment remain the same as that of the previous embodiment inthat the spring contact 200 includes an upper contact pin 210, a lowercontact pin 220 assembled to the upper contact pin 210 such that theupper and lower contact pins 210 and 220 cross each other, and a spring230 elastically supporting the upper and lower contact pins 210 and 220,and in that the upper and lower contact pins 210 and 220 are commonlyprovided by the use of a single contact pin.

The upper contact pin 210 remains the same as that of the previousembodiment in that the upper contact pin 210 includes a body portion 212including a groove 111 that is recessed in each of opposite surfacesthereof, a shoulder protrusion 213 formed to protrude vertically fromeach of left and right side ends of the body portion 212, a pair ofelastic portions 215 extending in a longitudinal direction of the bodyportion 212 to be bilaterally symmetrical to each other, a second endcontact portion 216 formed at an end of each of the elastic portions215, and a guide surface 217. In particular, the upper contact pin 210in the present embodiment includes one first end contact portion 214extending on the central axis.

The first end contact portion 214 includes an edge line formed by twodifferent inclined contact surfaces that are in contact with each other.Herein, the contact surfaces may be provided by the use of curvedsurfaces. Meanwhile, a height k of the first end contact portion 214from the respective shoulder protrusions 213 may be determined inconsideration of the height of the lead of the IC.

A total length L1 of the spring contact 200 of the present embodimentconfigured as described above in a compressed state is the same as thelength of a single contact pin. Herein, the first end contact portion214 of the upper contact pin 210 and second end contact portions 226 ofthe lower contact pin 220, which define an upper end portion of thespring contact 200, come into contact with the lead 2 of the ICsimultaneously at three positions 214A and 226A.

As such, the first end contact portion 214 of the upper contact pin 210may include a single edge line or two or more corner edge linesdepending on the lead of the IC.

Second Embodiment

FIGS. 11A and 11Bb are respectively a plan view and a front viewillustrating a spring contact according to a second embodiment of thepresent invention, and FIG. 12 is an exploded view illustrating thespring contact according to the second embodiment of the presentinvention.

Referring to FIGS. 11A, 11B, and 11C and FIG. 12, a spring contact 300of the present embodiment includes an upper contact pin 310, a lowercontact pin 320 assembled to the upper contact pin 310 such that theupper and lower contact pins 310 and 320 cross each other, and a spring330 elastically supporting the upper and lower contact pins 310 and 320.

Preferably, the upper contact pin 310 includes a cylindrical headportion 314 provided at an upper portion thereof and having apredetermined outer diameter d. The head portion 314 is formedintegrally with a body portion 312 constituting the upper contact pin310 and may be provided by rolling a plate manufactured by stamping intoa substantially “S” shape. The outer diameter d of the head portion 314is appropriately determined in consideration of the size of a lead(ball) of an IC. Preferably, the width between two shoulder protrusions313 protruding horizontally from left and right sides of the bodyportion 312 to support the spring 330 is larger than the outer diameterd of the head portion 314.

In the present embodiment, the lower contact pin 320 is substantiallythe same as the plate-shaped contact pin of the first embodiment, andthus a duplicate description is omitted.

The spring 330 is provided by the use of a coiled compression springthat resists the compressive force. The spring 330 is provided betweenthe upper contact pin 310 and the lower contact pin 320 to provide arestoring force for returning the upper contact pin 310 and the lowercontact pin 320 to original positions thereof when the upper contact pin310 and the lower contact pin 320 are compressed in longitudinaldirections thereof.

FIGS. 13A and 13B are respectively a front view and a side viewillustrating an unfolded state of the upper contact pin of the springcontact according to the second embodiment of the present invention.

Referring to FIG. 13, the plate-shaped upper contact pin 310′ includes astrip 314′ integrally and horizontally provided at an upper portion ofthe body portion 312, and first end contact portions 314 a are providedat an upper end of the strip 314′.

The strip 314′ has the same left and right lengths with respect to acenter C1 of the body portion 312 and is rolled to have a cylindricalshape.

In detail, the strip 314′ forms the cylindrical head portion 314including a first strip section 3411 located on the same plane as thebody portion 312 and provided to have the same left and right distancesfrom the center C1 of the body portion 312, and a second strip section3314 rolled clockwise (or counterclockwise) at each of opposite ends ofthe first strip section 3411 to have a semi-circular arc shape. The headportion 314 having such a structure has an approximately “S” shape in aplan (see FIG. 11A). Meanwhile, the head portion 314 may have abilaterally symmetrical shape of “S” in a plane depending on the rollingdirection of the respective second strip sections 3314.

The first strip section 3411 is located in a radial direction of thecylindrical head portion 314, and thus a length d thereof correspondsapproximately to a cylindrical diameter. A sum of lengths R/2 of therespective second strip sections 3314 provided at the opposite ends ofthe first strip section 3411 corresponds to a cylindrical circumferenceR of the head portion 314. Therefore, a sum R of the length d of thefirst strip section 3411 and the lengths of the two second stripsections 3412 fulfills a relationship of R (length of the cylindricalcircumference)=d (diameter of the circle)

(radius).

The body portion 312 includes a groove 311 formed in each of oppositesurfaces thereof in a longitudinal direction thereof, a shoulderprotrusion 313 formed at each of left and right side ends of the bodyportion to support the spring 330, a pair of elastic portions 315extending downward to be bilaterally symmetrical to each other in thelongitudinal direction of the body portion 312, and a second endprotrusion 315 a formed at an end of each of the elastic portions 315.This configuration is substantially the same as that of the previousfirst embodiment.

FIGS. 14A and 14B are front views illustrating the spring contactaccording to the second embodiment of the present invention. FIGS. 14Aand 14B are views in directions perpendicular to each other, whichillustrate the spring contact in plan view.

In FIGS. 14A and 14B, the lower contact pin 320 includes one end contactportion 326 provided at a lower end thereof. However, the shape of theend contact portion of the lower contact pin 320 is not limited theretoand may be variously modified depending on the type or size of leads.

FIGS. 15A and 15B are views illustrating a spring contact according to amodification of the second embodiment of the present invention. A springcontact 400 of the present embodiment includes an upper contact pin 410and a lower contact pin 420 which are provided by the use of contactpins of the same shape.

As described above, it will be appreciated that in each embodiment,upper and lower contact pins having the same shape may be assembled witheach other, or depending on the type of leads, upper and lower contactpins may be provided by the use of a combination of two differentcontact pins having end contact portions of the structure suitable forthe same.

Third Embodiment

FIGS. 16 to 18 are views illustrating a spring contact according to athird embodiment of the present invention. FIG. is a front viewillustrating the spring contact in a partially cutaway state, FIG. 17 isa front view illustrating an unfolded state of the spring contact beforerolling, and FIG. 18 is a side view illustrating the unfolded state.

As illustrated in FIG. 16, a spring contact 500 of the presentembodiment is characterized by being integrally formed in such a mannerthat a strip pattern formed by punching out a metal plate is rolled intoa cylindrical shape.

In detail, referring to FIGS. 17 and 18, a strip pattern 500′ of thespring contact includes an elastic portion 511 in which a unit strip 511a and 511 b comprised of a horizontal strip 511 a and a vertical strip511 b are connected to each other in a zigzag pattern, an upper headportion 512 that extends from an uppermost end of the elastic portion511 and includes upper end portions 512 a protruding upward, a lowerhead portion 513 that extends from a lowermost end of the elasticportion 511 and includes lower end portions 513 a protruding downward.

The spring contact may be manufactured by punching a plate mainly madeof beryllium copper (BeCu), copper alloy, or stainless steel (SUS) in apredetermined pattern and bending the plate in a cylindrical shape toobtain a contact. Palladium (Pd), palladium (PdNi), palladium nickel(PdNi), or palladium cobalt (PdCo) may be plated on the surface of thecontact.

The elastic portion 511 includes the unit strip 511 a and 511 b, theunit strip being comprised of the horizontal strip 511 a, and thevertical strip 511 b extending vertically from one end of the horizontalstrip 511 a and having a shorter length than the horizontal strip 511 a.A plurality of unit strips 511 a and 511 b are connected to each otherin a zigzag pattern.

The upper head portion 512 and the lower head portion 513 respectivelyinclude the upper end portions 512 a and the lower end portions 513 beach of which are comprised of a plurality of teeth formed along theedge, and the upper end portions 512 a and the lower end portions 513 bcome into contact with a lead of an IC and a lead of a PCB.

In the present embodiment, the upper head portion 512 and the lower headportion 513 are illustrated as the same as the horizontal strip 511 a ofthe elastic portion 511. However, the present invention is not limitedthereto. For example, the width and length may be different.

The plate-shaped strip pattern 510′ undergoes bending in a cylindricalshape. The strip pattern 510′ is bent in a cylindrical shape with thecenter of the horizontal strip 511 a as a vertical axis C2.

Meanwhile, the spring contact 500 of the present embodiment may beprovided by the use of various strip patterns. For example, there may bevarious modifications such as a strip pattern in which a plurality ofclosed loops are connected to each other in a longitudinal direction ina partial section of the elastic portion, a spiral strip pattern, or thelike.

FIGS. 19A and 19B and FIGS. 20A and 20B are views illustratingmodifications of the third embodiment of the present invention.

Referring to FIGS. 19A and 19B, a spring contact 600 according to amodification includes a contact unit 610 integrally formed by rolling astrip pattern formed by punching a metal plate into a cylindrical shape,and a coil inserted into the contact unit 610.

Preferably, the outer diameter of the coil spring 620 is smaller thanthe inner diameter of the contact unit 610 such that the contact unit610 and the coil spring 620 have a suitable clearance so as not tointerfere with each other during operation.

Referring to FIGS. 20A and 20B, a spring contact 700 according toanother modification includes a first contact unit 710 integrally formedby rolling a strip pattern formed by punching a metal plate into acylindrical shape, and a second contact unit 720 inserted into the firstcontact unit 710. The second contact unit 720 is manufactured in thesame manner by rolling a strip pattern formed by punching a metal plateinto a cylindrical shape.

The first contact unit 710 and the second contact unit 720 may beprovided by the use of the same strip pattern. Alternatively, the firstcontact unit 710 and the second contact unit 720 may have differentstrip patterns.

The outer diameter of the second contact unit 720 is smaller than theinner diameter of the first contact unit 710 such that the first contactunit 710 and the second contact unit 720 have a suitable clearance so asnot to interfere with each other during operation.

Hereinafter, a test socket including spring contacts will be describedin detail.

First Embodiment

FIG. 21 is a plan view illustrating a test socket according to a firstembodiment of the present invention, and FIG. 22 is a sectional viewtaken along line E-E of FIG. 21. For reference, in FIG. 21, an uppercontact pin 210 and a lower contact pin 220 constituting a springcontact 200 are assembled to vertically cross each other. However, theupper contact pin 210 and the lower contact pin 220 are illustrated asassembled on the same plane for ease of understanding.

Referring to FIGS. 21 and 22, a test socket 1100 of the presentembodiment includes: a plurality of spring contacts 220 each of whichincludes the upper contact pin 210, the lower contact pin 220 assembledto the upper contact pin 210 such that the upper and lower contact pins210 and 220 cross each other to mutually linearly operate, and a coilspring 230 elastically supporting the upper contact pin 210 and thelower contact pin 220; a main plate 1110 having a plurality ofaccommodating holes 1111 in which the respective spring contacts 200 areaccommodated; and a film plate 1120 provided on a lower portion of themain plate 1110.

Preferably, the main plate 1110 has first openings 1113 each of whichhas a diameter d2 smaller than a diameter d1 of each of theaccommodating holes 1111 formed to support each of the respective uppercontact pins 210 by a stepped portion 1112 protruding horizontally froman upper opening end of each of the accommodating holes 1111. In detail,the diameter d2 of each of the first openings 1113 is smaller than thewidth of shoulder protrusions 213 formed at each of the upper contactpins 210.

The film plate 1120 is attached to a lower portion of the main plate1110 and has second openings 1121 each of which is formed at a positioncorresponding to each of the accommodating holes 1111 to have a diameterd3 smaller than the diameter d1 of the accommodating hole 1111. Indetail, the diameter d3 of each of the second openings 1121 is smallerthan the width of shoulder protrusions 223 of each of the respectivelower contact pins 220.

The test socket 1100 may include at least one mounting hole 1101 formounting the socket, and a guide hole 1102 for guiding the socket to bepositioned in place. In the present embodiment, the mounting hole 1101and the guide hole 1102 are illustrated as formed through the main plate1110 and the film plate 1120.

In the test socket 1100, the upward movement of the upper contact pins210 1111 are limited in the accommodating holes by the respectivestepped portions 1112 and the downward movement of the lower contactpins 220 are limited by the film plate 1120, whereby leads of an IC andleads of a PCB are elastically connected to each other by the respectivecoil springs 230.

An assembly process of the spring contacts 200 and the test socket 1100may be performed in such a manner that the spring contacts 200 are firstinserted into the respective lower openings of the accommodating holes1111 and then the film plate 1120 is attached to a lower surface of themain plate 1110. On the other hand, the film plate 1120 may be attachedto the main plate 1120 first, and then the spring contacts 200 may beforcibly inserted into the respective second openings 1121 of the filmplate 1120.

Second Embodiment

FIG. 23 is a sectional view illustrating a test socket according to asecond embodiment of the present invention.

Referring to FIG. 23, a test socket 1200 according to the presentembodiment includes spring contacts 100 each of which includes twocontact pins 110 and 120 elastically supported by a coil spring 130 andassembled to cross each other, a main plate 1210 in which the springcontacts 100 are accommodated, and a film plate 1220. This configurationremains the same as that of the first embodiment.

In the present embodiment, the main plate 1210 has pocket holes 1214formed in an upper surface thereof, each of the pocket holes 1214 beingwider than a diameter d2 of each of first openings 1213 to accommodateeach lead ball 71 of an IC.

The height and diameter of the pocket holes 1214 is determined inconsideration of the size of lead balls 71 of the IC. Each of the pocketholes 1214 is configured such that an upper opening end thereof has acurved surface. This configuration allows that when the IC is loadedinto the test socket 1200, the lead balls 71 can be guided to therespective pocket holes 1214 along the curved surfaces and thus the leadballs 71 and the spring contacts 100 can come into contact with eachother at correct positions.

In the present embodiment, each of the spring contacts 100 isillustrated that an end contact portion of the upper contact pin 110 isconfigured as a pair, and the shape of the end contact portion of eachcontact pin may vary depending on the leads of the IC.

Third Embodiment

FIG. 24 is a sectional view illustrating a test socket according to athird embodiment of the present invention.

As illustrated in FIG. 24, a test socket 1300 of the present embodimentincludes spring contacts 200 each of which includes two contact pins 210and 220 elastically supported by a coil spring 230 and assembled tocross each other, a main plate 1310 having a plurality of accommodatingholes 1311 in which the respective spring contacts 200 are accommodated,and a silicone caulking part 1320 inserted into a lower opening end ofeach of the accommodating holes 1311 to fix each lower contact pin 220to the main plate 1310.

Similarly to the previous first embodiment, the main plate 1310 includesfirst openings 1313 each of which has a diameter d2 smaller than adiameter d1 of each of the accommodating holes 1311 support formed toeach of the respective upper contact pins 210 by a stepped portion 1312protruding horizontally from an upper opening end of each of theaccommodating holes 1311.

The respective silicone caulking parts 1320 are inserted into theaccommodating holes 1311 to predetermined depths after the springcontacts 200 are inserted into the accommodating holes 1311 throughlower openings of the accommodating holes 1311 to be temporarilyassembled to the main plate 1310, whereby the respective lower contactpins 220 are fixed to the main plate 1310.

The silicone caulking parts 1320 may be provided by the use of anelastic silicone rubber. The silicone caulking parts 1320 fix lower endsof the lower contact pins 220 while being compressed within the elasticrange of the material of the silicone caulking parts 1320 themselves.

Preferably, insertion depths of the silicone caulking parts 1320 arereached appropriately to depths of shoulder protrusions 223 of the lowercontact pins 220. This is because elastic deformation of the respectivecoil springs 230 may be interfered with when the insertion depths aregreater than the depths of shoulder protrusions 223.

Meanwhile, in the present embodiment, the main plate 1310 may havepocket holes (refer to the second embodiment) formed in an upper portionthereof to accommodate lead balls of an IC.

Fourth Embodiment

FIG. 25 is a sectional view illustrating a test socket according to afourth embodiment of the present invention.

Referring to FIG. 25, a test socket 1400 of the present embodimentincludes: a plurality of spring contacts 200 each of which includes twocontact pins 210 and 220 elastically supported by a coil spring 230 andassembled to cross each other; a lower film plate 1410 having aplurality of first through-holes 1411 through which the respectivespring contacts 100 are positioned; a mounting part 1420 provided on anupper side of the lower film plate 1410; an insulating body 1430provided on an upper side of the mounting part 1420 and having secondthrough-holes 1431 formed corresponding to the first through-holes 1411to accommodate the spring contacts 100; an upper film plate 1440provided on an upper surface of the insulating body 1430 and havingthird through-holes 1441 formed corresponding to the secondthrough-holes 1431; and a first silicone caulking part 1451 insertedinto an upper portion of each of the second through-holes 1431 of theinsulating body 1430 to fix each of the respective upper contact pins210 to the insulating body 1430.

The lower film plate 1410, the insulating body 1430, and the upper filmplate 1430 are integrally formed to have a predetermined thickness andinclude the through-holes 1411, 1431, and 1441, respectively. The springcontacts 100 are inserted into the through-holes 1411, 1431, and 1441,and the upper contact pins 110 are fixed integrally with the insulatingbody 1430 by the respective first silicone caulking parts 1451. Thefirst through-holes 1411, the second through-holes 1431, and the thirdthrough-holes 1441 have the same inner diameter. Preferably, at leastthe second through-holes 1431 have outer diameters larger than maximumouter diameters of the spring contacts 100 to avoid interference withthe operation of the spring contacts 100 when the spring contacts 100accommodated therein are moved upward and downward.

The first silicone caulking parts 1451 may be provided by the use of anelastic silicone rubber. The silicone caulking parts 1451 fix lower endsof the lower contact pins 220 while being compressed within the elasticrange of the material of the silicone caulking parts 1451 themselves.Preferably, insertion depths of the silicone caulking parts 1451 arereached appropriately to depths of shoulder protrusions 113 of the uppercontact pins 110.

Preferably, a second silicone caulking part 1452 may be inserted into alower portion of each of the second through-holes 1431 of the insulatingbody 1430 and molded whereby the insulating body 1430 and the lowercontact pins 120 may fixedly supported.

The insulating body 1430 may be provided by the use of an elastomericsuch as an elastic silicone rubber. In this case, the insulating bodymade of the elastomeric may be manufactured in such a manner that aliquid resin is injected into a separate mold and is cured. Therefore,it is easy to manufacture as compared to a conventional method ofinjecting synthetic resin.

The mounting part 1420 may include a mounting hole for assembling thesocket and a guide hole for guiding the socket in position. Areinforcing plate 350 may be provided by the use of metal (SUS) orresin.

A first adjustment plate 1462 for height adjustment may be provided on alower surface of the lower film plate 1410. In addition, a secondadjustment plate 1462 for height adjustment may be provided on an uppersurface of the upper film plate 1440.

FIG. 26 illustrates a modification of the fourth embodiment of thepresent invention. A test socket in the present embodiment may includedifferent spring contacts 100 and 200 to be suitable for leads of ahybrid IC in which a BGA type and a LGA type are mixed.

The hybrid IC 70 includes ball-type leads 71 and land-type leads 72having different heights d4 and d5, and correspondingly thereto, asocket 1400 includes first spring contacts 100 and second springcontacts 200 having different heights in accordance with the type of therespective leads.

First silicone caulking parts 1451 and second silicone caulking parts1452 are inserted into upper ends of the first spring contacts 100 andlower ends of the second spring contact 200, respectively, to be fixedto and supported by an insulating body 1430.

In the present embodiment, the first spring contacts 100 each of whichincludes an upper contact pin having a pair of first end contactportions 114 are provided at positions of the ball-type leads 71, whilethe second spring contacts 200 each of which includes an upper contactpin having one first end contact portion 214 are provided at positionsof the land-type leads 72.

As described above, the spring contacts according to the presentinvention have a high degree of design freedom with respect to theheight or shape of the first end contact portions at upper ends of thecontact pins. For this reason, the socket 400 may include the differentfirst and second spring contacts 100 and 200 having a height differenced6 so as to compensate for a height difference d4-d5 according to thelead type when the IC is loaded.

Fifth Embodiment

FIG. 27 is a sectional view illustrating a test socket according to afifth embodiment of the present invention.

Referring to FIG. 27, a test socket 1500 of the present embodimentincludes a plurality of spring contacts 300 each of which includes twocontact pins 310 and 320 elastically supported by a coil spring 330 andassembled to cross each other, a main plate 1510 having a plurality ofaccommodating holes 1511 in which the spring contacts 300 areaccommodated, and a film plate 1520 provided on a lower portion of themain plate 1510. The other configurations remain substantially the sameas those of the test socket according to the first embodiment, exceptfor the spring contacts 300.

In the present embodiment, the upper contact pin 310 of each of thespring contacts 300 includes a cylindrical head portion 314.

Each of the spring contacts 300 is accommodated in each of theaccommodating holes such that shoulder protrusions 313 of the uppercontact pin 310 are limited to move upward in contact with each steppedportion 1512, and shoulder protrusions (not illustrated) of the lowercontact pin 320 are limited to move downward by being supported by thefilm plate 1520. Meanwhile, the head portion 314 of each of therespective upper contact pins 310 has a smaller inner diameter than thatof the stepped portion 1512, and thus, upper ends of the respective headportions 314 of the upper contact pins 310 can be located in pocketholes 1514 to come into contact with lead balls 81.

In particular, when leads of an IC are ball-type leads, the provision ofthe cylindrical head portions 314 at the upper ends of the upper contactpins 310 enables more stable contact with the lead balls 81, therebymaking it possible to reduce the contact resistance.

Meanwhile, in the present exemplary embodiment, the film plate 1520 isattached to a lower portion of the main plate 1510 to fix and supportlower ends of the spring contacts 300. However, as described in theprevious embodiments, silicone caulking parts may be directly injectedinto lower openings of the spring contacts to fix the lower ends of thespring contacts, without provision of a separate film plate.

Sixth Embodiment

FIG. 28 is a sectional view illustrating a test socket according to asixth embodiment of the present invention.

As illustrated in FIG. 28, spring contacts 300 each of which includes acylindrical head portion 314 are applicable to the structure of thespring contacts (see FIG. 25) of the fourth embodiment described above.

In detail, a test socket 1600 of the present embodiment is configuredsuch that first silicone caulking parts 1651 and second siliconecaulking parts 1652 are injected into upper opening ends ofthrough-holes 1611 and lower opening ends of through-holes 1631,respectively, in a state in which the spring contacts 300 areaccommodated in the second through-holes 1631 of an insulating body1630, whereby upper ends of upper contact pins 310 and lower ends oflower contact pins 320 are fixed to and supported by the insulating body1630.

Seventh Embodiment

FIG. 29 is a sectional view illustrating a test socket according to aseventh embodiment of the present invention.

As illustrated in FIG. 29, spring contacts 500 having a structure bentin a cylindrical shape are applicable to the structure of the springcontacts (see FIG. 25) of the fourth embodiment described above.

In detail, a test socket 1700 of the present embodiment is configuredsuch that first silicone caulking parts 1751 and second siliconecaulking parts 1752 are injected into upper and lower opening ends ofthrough-holes, respectively, in a state in which the spring contacts 500bent in a cylindrical shape are accommodated in second through-holes ofan insulating body 1730, whereby upper and lower ends of the springcontacts 500 are fixed to and supported by the insulating body 1730.

The structure of the test socket 1700 is not particularly limited aslong as the spring contacts 500 have an overall cylindrical shape andintend to provide elastic force in an axial direction. For example, adouble cylindrical structure described with reference to FIGS. 19A and19B and FIGS. 20A and 20B may also be applicable in the same manner.

Although exemplary embodiments of the present invention have beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas defined by the appended claims.

What is claimed is:
 1. A test socket with spring contacts, the testsocket comprising: a plurality of spring contacts each of which includesan upper contact pin, and a lower contact pin assembled to the uppercontact pin such that the upper and lower contact pins cross each otherto mutually linearly operate, and a spring elastically supporting theupper contact pin and the lower contact pin; a main plate having aplurality of accommodating holes in which the respective spring contactsare accommodated, with first openings each having a diameter (d2)smaller than a diameter (d1) of each of the accommodating holes formedto support each of the respective upper contact pins by a steppedportion protruding horizontally from an upper opening end of each of theaccommodating holes; and a film plate provided on a lower portion of themain plate, and having second openings each formed at a positioncorresponding to each of the accommodating holes to have a diameter (d3)smaller than the diameter (d1) of the accommodating hole to support eachof the respective lower contact pins.
 2. A test socket with springcontacts, the test socket comprising: a plurality of spring contactseach of which includes an upper contact pin, and a lower contact pinassembled to the upper contact pin such that the upper and lower contactpins cross each other to mutually linearly operate, and a springelastically supporting the upper contact pin and the lower contact pin;a main plate having a plurality of accommodating holes in which therespective spring contacts are accommodated, with first openings eachhaving a diameter (d2) smaller than a diameter (d1) of each of theaccommodating holes formed to support each of the respective uppercontact pins by a stepped portion protruding horizontally from an upperopening end of each of the accommodating holes; and a silicone caulkingpart inserted into a lower opening end of each of the accommodatingholes to fix each of the respective lower contact pins to the mainplate.
 3. The test socket of claim 1, wherein the main plate has pocketholes formed in an upper surface thereof and being wider than a diameter(d2) of each of the respective first openings to accommodate each leadof an IC.
 4. The test socket of claim 2, wherein the main plate haspocket holes formed in an upper surface thereof and being wider than adiameter (d2) of each of the respective first openings to accommodateeach lead of an IC.
 5. A test socket with built-in contacts, the testsocket comprising: a plurality of spring contacts each of which includesan upper contact pin, and a lower contact pin assembled to the uppercontact pin such that the upper and lower contact pins cross each otherto mutually linearly operate, and a spring elastically supporting theupper contact pin and the lower contact pin; a lower film plate having aplurality of first through-holes through which the respective springcontacts are positioned; a mounting part provided on an upper side ofthe lower film plate; an insulating body provided on an upper side ofthe mounting part and having second through-holes formed correspondingto the first through-holes to accommodate the spring contacts; an upperfilm plate provided on an upper surface of the insulating body andhaving third through-holes formed corresponding to the secondthrough-holes; and a first silicone caulking part inserted into an upperportion of each of the second through-holes of the insulating body tofix each of the respective upper contact pins to the insulating body. 6.A test socket with built-in contacts, the test socket comprising: aplurality of spring contact each of which is integrally formed in such amanner that a strip pattern formed by punching out a metal plate isrolled into a cylindrical shape; a lower film plate having a pluralityof first through-holes through which the respective spring contacts arepositioned; a mounting part provided on an upper side of the lower filmplate; an insulating body provided on an upper side of the mounting partand having second through-holes formed corresponding to the firstthrough-holes to accommodate the spring contacts; an upper film plateprovided on an upper surface of the insulating body and having thirdthrough-holes formed corresponding to the second through-holes; and afirst silicone caulking part inserted into an upper portion of each ofthe second through-holes of the insulating body to fix an upper end ofeach of the spring contacts to the insulating body.
 7. The test socketof claim 5, further comprising: a second silicone caulking part insertedinto a lower portion of each of the second through-holes of theinsulating body to fix a lower end of each of the spring contacts to theinsulating body.
 8. The test socket of claim 6, further comprising: asecond silicone caulking part inserted into a lower portion of each ofthe second through-holes of the insulating body to fix a lower end ofeach of the spring contacts to the insulating body.
 9. The test socketof claim 6, wherein each of the spring contacts includes a first contactunit formed by rolling a strip pattern and having elasticity andconductivity in an axial direction, and a second contact unit insertedinto the first contact unit and having elasticity and conductivity in anaxial direction.
 10. The test socket of claim 1, wherein each contactpin further includes a cylindrical head portion provided at an endthereof that comes into contact with each lead ball and having aprotruding upper end portion.
 11. The test socket of claim 3, whereineach contact pin further includes a cylindrical head portion provided atan end thereof that comes into contact with each lead ball and having aprotruding upper end portion.
 12. The test socket of claim 4, whereineach contact pin further includes a cylindrical head portion provided atan end thereof that comes into contact with each lead ball and having aprotruding upper end portion.
 13. The test socket of claim 5, whereineach contact pin further includes a cylindrical head portion provided atan end thereof that comes into contact with each lead ball and having aprotruding upper end portion.
 14. A spring contact, comprising: a firstcontact pin; a second contact pin assembled to the first contact pinsuch that the first and second contact pins cross each other; and a coilspring elastically supporting the first contact pin and the secondcontact pin, wherein each of the first contact pin and the secondcontact pin includes: a body portion including a groove that is recessedin each of opposite surfaces thereof in a longitudinal directionthereof; a pair of shoulder protrusions protruding from each of left andright side ends of the body portion to support the coil spring; a firstend contact portion extending from an upper end of the body portion; apair of elastic portions extending in the longitudinal direction of thebody portion to be bilaterally symmetrical to each other, and each ofwhich includes a guide surface protruding inward from an end portion ofeach of the elastic portions such that the respective guide surfacesface each other; and a second end contact portion extending from an endof each of the elastic portions, wherein at least one of the first endcontact portion and the second end contact portion includes a headportion formed at the upper end of the body portion and made of aplate-shaped strip, the strip having same left and right lengths withrespect to of a center of the body portion, with an upper end alongwhich the first end contact portion is formed, and the strip includes afirst strip section located on the same plane as the body portion andprovided to have the same left and right distances from the center ofthe body portion, and a second strip section rolled at each of oppositeends of the first strip section to have a semi-circular arc shape, suchthat the first strip section is located in a radial direction of acylindrical shape formed by the entire second strip section.
 15. Thespring contact of claim 14, wherein the first and second contact pinshave the same shape.